For one of the safety systems of vehicles, an alarm system is commercially available. The alarm system gives a warning that a person on a car does not wear a seat belt. In the case in which the alarm system detects that a person takes a seat but not wear a seat belt, the alarm system gives a warning. For a seat device for use in such alarm systems, Patent Literature 1 below is proposed.
A seat device according to Patent Literature 1 includes a flexible seat pressure sensitive switch (PSS/PSS2) accommodated in a recess (C1a) formed on the back face of a seat cushion (C1) and an elastic stopper (C2) in contact with the under face of the pressure sensitive switch (PSS/PSS2) to close the recess (C1a).
In this seat device, a load applied to one point is dispersed by the seat cushion (C1). Thus, no large load is locally applied to the pressure sensitive switch (PSS/PSS2), which allows the pressure sensitive switch (PSS/PSS2) to have a high durability.
[Patent Literature 1] JP-A-10-211836